Rotary valves are used in industry for a number of applications like controlling the flow of liquids to molds and reactors, regulating the flow of hydraulic fluids to control various machine functions, and controlling fluids which impinge upon work pieces. The majority of these applications take place at relatively low rotational speed and/or in a stepwise manner, relatively low temperature and pressure, and a number of suitable control means have been developed.
Suitable means for prior fluid regulation valve applications have been gate valves, ball valves, etc., rotating shafts with oddly shaped voids, through the use of electronic means such as solenoids, and by using disks having holes to redirect the flow stream. One example of a valve is that of U.S. Pat. No. 5,014,748 to Nogami et al. which shows a valve which directs the fluid through a number of irregular voids in discs and in stationary parts which align and unalign in specific ways to direct and redirect the fluid to the exit. Another such valve is that of U.S. Pat. No. 3,124,162 to Cameron which uses a solenoid. U.S. Pat. No. 4,802,508 to Styles et al. redirects fluid flow to multiple ports. Other complex valving systems exist, e. g. as shown in U.S. Pat. No. 3,422,848.
Such methods are effective for some applications which generally take place at lower speeds and temperature but are not fully satisfactory for high temperature and high speed applications. The regulation of fluid flow with solenoids, for example, relies on something which undergoes a reciprocating motion and so is subject to significant jarring action and as such is prone to failure. Solenoids have the further drawback of requiring an electrical input for operation as well as for signaling when to open and close and of having an upper frequency limit of about 50 Hz. Because solenoids move in a reciprocating fashion, they also have a further limitation which is the amount of fluid which they can process, since regulating a large flow would require a large solenoid and the mass of the valve itself becomes prohibitively large for rapid reversal of direction.
Other methods of regulating flow force the fluid to travel through various tortuous paths, repeatedly changing direction, prior to exiting the device. Such a method of turning and returning the flow stream results in time delays in the output stream and can be quite mechanically complicated.
There remains, therefore, a need for a means of controlling the flow of a fluid for high speed changes, e.g. fluid pulses or perturbations, which is relatively simple in design and suited for high temperature applications. Such a valve may be used in applications such as creating aerosols of liquids and gases (e.g. carburation of fuels, pesticide application, paint spraying) and in nonwoven fiber production. It is therefore an object of this invention to provide a high speed valve which creates perturbations in a fluid flow stream.